scholarly journals Molecular malaria surveillance using a novel protocol for extraction and analysis of nucleic acids retained on used rapid diagnostic tests

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Etienne A. Guirou ◽  
Tobias Schindler ◽  
Salome Hosch ◽  
Olivier Tresor Donfack ◽  
Charlene Aya Yoboue ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Malaria Surveillance

scholarly journals Molecular malaria surveillance using a novel protocol for extraction and analysis of nucleic acids retained on used rapid diagnostic tests

2020 ◽  
Author(s):  
Etienne A. Guirou ◽  
Tobias Schindler ◽  
Salome Hosch ◽  
Olivier Tresor Donfack ◽  
Charlene Aya Yoboue ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Diagnostic Tests ◽  
Large Scale ◽  
Rapid Diagnostic Tests ◽  
Nucleic Acid Amplification ◽  
Nucleotide Polymorphisms ◽  
Sample Collection ◽  
Malaria Surveillance ◽  
Bioko Island ◽  
Asymptomatic Patients

AbstractThe use of malaria rapid diagnostic tests (RDTs) as a source for nucleic acids that can be analyzed via nucleic acid amplification techniques has several advantages, including minimal amounts of blood, sample collection, simplified storage and shipping conditions at room temperature. We have systematically developed and extensively evaluated a procedure to extract total nucleic acids from used malaria RDTs. The co-extraction of DNA and RNA molecules from small volumes of dried blood retained on the RDTs allows detection and quantification of P. falciparum parasites from asymptomatic patients with parasite densities as low as 1 Pf/µL blood using reverse transcription quantitative PCR. Based on the extraction protocol we have developed the ENAR (Extraction of Nucleic Acids from RDTs) approach; a complete workflow for large-scale molecular malaria surveillance. Using RDTs collected during a malaria indicator survey we demonstrated that ENAR provides a powerful tool to analyze nucleic acids from thousands of RDTs in a standardized and high-throughput manner. We found several, known and new, non-synonymous single nucleotide polymorphisms in the propeller region of the kelch 13 gene among isolates circulating on Bioko Island, Equatorial Guinea.

scholarly journals Analysis of nucleic acids extracted from rapid diagnostic tests reveals a significant proportion of false positive test results associated with recent malaria treatment

2021 ◽  
Author(s):  
Salome Hosch ◽  
Charlene Aya Yoboue ◽  
Olivier Tresor Donfack ◽  
Etienne A Guirou ◽  
Jean-Pierre Dangy ◽  
...  
Keyword(s):  
Quality Control ◽  
Nucleic Acids ◽  
False Positive ◽  
Diagnostic Tests ◽  
False Negative ◽  
Rapid Diagnostic Tests ◽  
Malaria Treatment ◽  
Malaria Surveillance ◽  
Bioko Island ◽  
Surveillance Programs

Surveillance programs often use malaria rapid diagnostic tests (RDTs) to determine the proportion of the population carrying parasites in their peripheral blood to assess the malaria transmission intensity. Despite an increasing number of reports on false-negative and false-positive RDT results, there is a lack of systematic quality control activities for RDTs deployed in malaria surveillance programs. Our study provides a larger scale comparative evaluation of RDTs used in the 2018 Malaria Indicator Survey (MIS) conducted on Bioko Island, Equatorial Guinea. We conducted a molecular analysis by extraction of nucleic acids from 1,800 negative and 1,065 positive RDTs followed by qPCR analysis. These results were combined with a dataset collected in a comprehensive questionnaire from each MIS participant. Of the 2,865 RDTs that were collected in 2018 on Bioko Island and analysed in our study, 4.7% had a false-negative result. These false-negative RDT results were associated with low parasite density infections. In a substantial proportion of samples, we identified masked pfhrp2 and pfhrp3 gene deletions in which at least one P. falciparum strain carried a gene deletion. Among all positive RDTs analysed, 28.4% were tested negative by qPCR and therefore considered to be false-positive. Analysing the questionnaire data collected from the participants, this high proportion of false-positive RDT results could be explained by PfHRP2 antigen persistence after recent malaria treatment. We conclude that malaria surveillance depending solely on RDTs needs well-integrated quality control procedures assessing the extend and impact of reduced sensitivity and specificity of RDTs on malaria control programs.

scholarly journals Plasmodium falciparum Allelic Diversity: A Comparison of DNA Extraction from Isolates Collected on Rapid Diagnostic Tests (Rdts) and Filter Paper

2021 ◽  
Author(s):  
Denise Patricia Mawili-Mboumba ◽  
Marie Louise Tshibola Mbuyi ◽  
Noe Patrick M’bondoukwe ◽  
Marielle Karine Bouyou-Akotet
Keyword(s):  
Plasmodium Falciparum ◽  
Nucleic Acids ◽  
Filter Paper ◽  
Diagnostic Tests ◽  
Allelic Diversity ◽  
Storage Conditions ◽  
Rapid Diagnostic Tests ◽  
Sample Collection ◽  
Filter Papers

Background: To perform molecular epidemiologic studies based on large cohorts, material such as RDTs or filter papers are useful for biological sample collection and extraction of RNA or DNA of good quality. Thus, we aimed to assess the quality of DNA extracted from malaria rapid diagnostic tests (RDTs) stored at various temperatures for the analysis of Plasmodium falciparum genetic diversity. Methods: Febrile patients benefitted from free malaria diagnosis using microscopy in a malaria sentinel site, at the Regional Hospital Estuaire-Melen, in Gabon, in 2015. P. falciparum isolates were collected onto one filter paper and 2 similar RDTs devices (Acon®) per patient. Nucleic acids were extracted with QiAmp Qiagen kit from paper and RDTs and the quality of the DNA was analyzed by msp1 gene amplification. Results: Msp1gene amplification was achieved in nucleic acids extracted from all filter papers and RDTs devices (n = 45, 100%). K1 alleles were detected in 93.3% (n = 42/45) of the samples and Mad20 alleles in 73.3% (n = 33/45). The number and the intensity of K1 and/or Mad20 fragments were comparable according to the sample collection material and the storage conditions (room temperature vs -20°C) of the samples. The size of the fragments indicating allelic diversity was comparable in 80% (n=36) of the samples. Conclusion: These data show that RDTs are a valuable source of DNA for malaria parasite genetic polymorphism analysis. Storage conditions of the devices did not influence the quality of DNA extracted from RDTs device, although some alleles may be missed.

scholarly journals Evaluation of the combination of Rapid Diagnostic Tests and microscopy for imported malaria surveillance in Anhui province, China

2020 ◽  
Author(s):  
Weidong Li ◽  
Xinzhou Zhang ◽  
Jun Feng ◽  
Tao Zhang ◽  
Xian Xu ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Anhui Province ◽  
Imported Malaria ◽  
Detection Methods ◽  
Malaria Surveillance ◽  
Predictive Values ◽  
Advantages And Disadvantages ◽  
Epidemiological Characteristics ◽  
Field Setting

Abstract Background In the Anhui province, China, efforts to halt local malaria transmission were successful, with no endemic cases reported since 2014. Contrastingly, imported malaria cases are still being reported, indicating a disease reintroduction risk after years of eradication. To avoid this reintroduction, rapid diagnostic tests (RDTs) were combined with microscopy methods to strengthen malaria surveillance. Herein, we aimed to evaluate the efficacy of this surveillance strategy in a field setting. Methods We conducted a retrospective study using malaria surveillance data from January 2016 to June 2020. Epidemiological characteristics and diagnostic information were analysed using descriptive and comparative statistics. The diagnostic performance of the combined toolbox (RDTs plus microscopy) was evaluated based on its sensitivity, specificity, positive and negative predictive values, and Cohen’s kappa coefficient. Results The combined toolbox displayed a higher overall sensitivity for malaria cases than that of microscopy alone (93.74% vs 89.37%; χ2 = 6.09; p = 0.14). In contrast to its high sensitivity, the combined toolbox had a specificity of 69.66%. The species identification rates of the combined toolbox for P. falciparum, P. vivax, P. ovale, and P. malariae were 83.15%, 65.00%, 42.11%, and 40.00%, respectively. Conclusions The combination of microscopy and RDTs is an effective strategy for malaria surveillance, possibly detecting more P. falciparum infections than microscopy alone. However, the specificity and ability to identify species of the combined toolbox were not optimal. Thus, monitoring malaria cases in non-endemic areas may require employing more than one diagnostic tool in surveillance strategies. Moreover, further understanding of the advantages and disadvantages of different detection methods is necessary for applying optimum combinations in the field setting.

Chronic Wasting Disease Options of Surveillance in Carpathian Cervids: from the Identification of Characteristic Microscopic Pathologic Changes to Prionic Seeded Conversion and Amplification Assays

2001 ◽  
Vol 71 (3) ◽  
pp. 480-486
Author(s):  
Florica Barbuceanu ◽  
Stelian Baraitareanu ◽  
Stefania-Felicia Barbuceanu ◽  
Gabriel Predoi
Keyword(s):  
Enzyme Immunoassay ◽  
Diagnostic Tests ◽  
Chronic Wasting Disease ◽  
Rapid Diagnostic Tests ◽  
Diagnostic Methods ◽  
Wasting Disease ◽  
Western Immunoblotting ◽  
Negative Results ◽  
Antigen Capture ◽  
Confirmatory Tests

This paper describes the current diagnostic methods of Chronic Wasting Disease (CWD) in cervides used between 2013 and 2017 in Romania. The active surveillance of CWD involves the targeted groups screening by using rapid diagnostic tests (e.g., antigen capture enzyme immunoassay). If the first test does not provide certain negative results, then the confirmatory methods have been used, i.e. histopathology, immunohistochemistry and Western immunoblotting. These tests did not lead to the detection of CWD prions (PrPCWD) in Romania. This may be due to the absence or insufficient quantity of PrPCWD in samples, below the threshold of confirmatory tests.

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